High-frequency oscillations of ictal muscle activity and epileptogenic discharges on intracranial EEG in a temporal lobe epilepsy patient

Clin Neurophysiol. 2008 Apr;119(4):862-8. doi: 10.1016/j.clinph.2007.12.014. Epub 2008 Mar 4.


Objective: During seizures, intracranial EEG electrodes can record ictal muscle movements. Our purpose was to differentiate the high-frequency oscillations (HFOs) of extracranial muscle contractions from those of intracranial epileptogenic discharges.

Methods: Using intracranial video-EEG (IVEEG), we recorded seizures in a 17-year-old boy with left mesial-temporal lobe epilepsy. We used multiple band frequency analysis (MBFA) to differentiate extracranial HFOs of craniofacial muscle activities from intracranial HFOs recorded ictally and interictally.

Results: During 11 seizures, IVEEG showed low-amplitude fast waves ( approximately 60Hz) starting at the left mesial-temporal electrodes. Ictal facial grimacing projected low-amplitude ( approximately 20muV) fast waves ( approximately 160Hz) on inferior lateral-temporal electrodes. Interictal chewing projected medium-amplitude ( approximately 100muV) fast waves ( approximately 140Hz) correlating to mouth movements. MBFA topographic power spectrograms revealed a sustained, consistent ictal fast-frequency band from electrodes in the seizure-onset zone and randomly scattered HFOs without a specific frequency band from ictal and interictal extracranial muscle contractions.

Conclusions: MBFA power spectrograms differentiated randomly scattered muscle HFOs without a specific frequency band at electrodes close to temporal muscles from ictal epileptic HFOs with a sustained, fast-frequency band in the seizure-onset zone.

Significance: The pattern and distribution of frequency power spectrograms of extracranial HFOs differ from those of intracranial HFOs.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Electroencephalography*
  • Epilepsy, Temporal Lobe / physiopathology*
  • Facial Muscles / physiology
  • Humans
  • Male
  • Muscle Contraction / physiology*
  • Muscle, Skeletal / physiology
  • Video Recording